Big campaign donations have always had a big influence on American politics, but the trend is getting worse. An analysis of campaign donations from last year by the Houston Chronicle showed that more candidates are relying on smaller groups of wealthy donors. Nationwide, 31,385 big donors provided nearly one-third of the $6 billion spent in last year's campaigns.

That process may be easier than broad-based efforts to attract smaller donations from more people, but it isolates candidates from their constituents.

A few candidates, like Texas Sen. Ted Cruz, covered both approaches. Big donors provided nearly one-third of his campaign funds, but he also had the most donations (17 percent of his total) under $200.

In most other campaigns, however, the difference was stark. Think about it: If you feel one way about an issue and the guy who writes the big check feels another way, who is more likely to influence the politician?